Chain door latch assembly

ABSTRACT

A combination door latch and safety chain assembly utilizes a single chain which functions as both a safety chain and latch. The chain is formed of a plurality of links serially interconnected for flexible movement by pivot means which restrict flexing of the chain to one plane. The pivot pins lie in a second plane perpendicular to said one plane. The chain is extendable from a barrel mounted to the door for engagement with a receiver on the door jamb and is manually rotatable for orientation with respect to the plane of the door. When the bolt disc on the end of the chain is engaged with the receiver and the chain is oriented with the plane of the pins substantially parallel to the door, the chain is flexible to door movement to function as a safety chain. And when the chain is oriented with the common plane of the pins substantially perpendicular to the door, the chain is inflexible so as to function as a lock or latch. The end of the chain opposite the bolt disc is secured to a spring inside the barrel so that the chain automatically retracts when the chain is disengaged from the receiver, or when the door is closed in the safety chain mode.

United States Patent n9} Draughon, Sr.

[lll 3,897,966

Aug. 5, 1975 l CHAIN DOOR LATCH ASSEMBLY [76] Inventor: Harry C.Draughon, Sr.. 4371 Glenwood Rd.. Apt. F Decatur. Ga 30032 22 Filed:June 27,1974

21 Appl. N0.:483,545

3.797.868 3/[974 Carey 292/262 Primary E.\'armner-Richard E. MooreAttorney. Agent, or FirnzLowe, King & Price [57] ABSTRACT A combinationdoor latch and safety chain assembly 3 we 0 4s utilizes a single chainwhich functions as both a safety chain and latch. The chain is formed ofa plurality of links serially interconnected for flexible movement bypivot means which restrict flexing of the chain to one plane. The pivotpins lie in a second plane perpendicular to said one plane. The chain isextendable from a barrel mounted to the door for engagement with areceivcr on the door jamb and is manually rotatable for orientation withrespect to the plane of the door. When the bolt disc on the end of thechain is engaged with the receiver and the chain is oriented with theplane of the pins substantially parallel to the door, the chain isflexible to door movement to function as a safety chain. And when thechain is oriented with the common plane of the pins substantiallyperpendicular to the door. the chain is inflexible so as to function asa lock or latch. The end of the chain opposite the bolt disc is securedto a spring inside the barrel so that the chain automatically retractswhen the chain is disengaged from the receiver. or when the door isclosed in the safety chain mode.

12 Claims. 6 Drawing Figures PATENTEU AUG 5 I975 FIG. 2

PATENIEB AUG 5l975 3.897, 965

SHEET 2 CH LOCK PO ON FIGS POSITION RELEASE SAFETY CHAIN POSITION CHAINDOOR LATCH ASSEMBLY FIELD OF THE INVENTION The present invention relatesgenerally to a door latching assembly and more particularly to a doorlatching assembly which functions as both a latch and safety chain.

DESCRIPTION OF THE PRIOR ART It is often desirable to provide a latch tosupplement a door lock, especially in areas having a high crime rate. Inaddition, in order to permit a person within a dwelling to ascertain whodesires admission before permitting him to enter, and to allow the doorto be left ajar when desired for the purpose of ventilation, it isuseful to include a means for permitting the door to be opened onlypartially.

In the most prevalent type of arrangement used heretofore, a slidinglatch is secured to the door opposite a latch receiver mounted in thejamb. When the door is closed, the latch is engageable with the receiverto bridge the gap between the door and jamb thereby preventing the doorfrom being opened. Generally, a separate chain is also provided which isconnectable between the door and another receiver on the jamb to permitthe door to be opened to the extent of the length of the chain. The doorcan be latched completely closed with the latch, or it can be allowed tobe opened partially by securing the free end of the chain to thereceiver before disengaging the latch. While generally satisfactory,this arrangement requires separate parts and separate manual operationsfor selectively latching and chaining the door. In addition, when thefree end of the chain is connected to the receiver on the jamb, thechain dangles between the mechanism and receiver creating an unsightlyappearance.

In a second type of mechanism of the prior art where an attempt has beenmade to combine the latch and chain functions, one end ofa chain isfastened to a bar which slides along the inside of a barrel to provide aretractable chain. When a locking portion of the bar is manually lodgedin a slot formed at the end of the barrel opposite the receiver, thechain is held fast fully retracted into the barrel. With the free end ofthe chain secured to the receiver, the chain tautly bridges the gapbetween the door and jamb tending to prevent opening the door. On theother hand, when the free end of the chain is secured to the receiverwith the bar lodged in a slot formed at the end of the barrel adjacentthe receiver, the chain hangs freely and the door may be opened to theextent of the length of the chain. This concept was proposed long ago inUS. Pat. No. 2l7,5 65 issued to T. P. White. The product, insofar as Iam aware, was never produced. It could have been generally satisfactory.However, in the latched position, there was no positive means to resistopening the door since the chain could flex in the direction of themovement. Also, the appearance of the chain dangling between the doorand jamb is unsightly and is an attractive nuisance for children. Anannoying clanking sound is created as the dangling chain strikes againstthe door in such an uncontrolled arrangement.

OBJECTS OF THE INVENTION Accordingly, it is one object of the presentinvention to provide a new and improved door latching assembly.

It is another object of the present invention to provide a new andimproved door latching assembly capable of selectively latching the doorclosed, or permit ting the door to be opened partially.

It is yet another object of the present invention to provide a new andimproved door latching assembly utilizing a single chain to both latchthe door closed and permit the door to be opened partially.

It is another object of the present invention to provide a new andimproved door latching assembly which is convertible for operationbetween that of a latch and of a safety chain.

It is another object of the present invention to provide a new andimproved door latching assembly having a safety chain that automaticallyretracts out of sight when the door is closed or the chain is not used.

BRIEF DESCRIPTION OF THE INVENTION A combination door latch and safetychain assembly uses a chain that is flexible in only one plane.Preferably housed in a barrel inside the door, the chain is formed of aplurality of links interconnected by pivot pins. The chain is supportedalong the axis of the barrel by a chain guide and, with a selector knobor lever, is manually rotatable to orient the common plane of the pinsto be either substantially parallel or perpendicular to the door.

The chain guide contains a pair of fingers between which the chain isheld. One end of the chain is secured to the interior of the barrel witha spring. An oblong bolt disc, connected to the other end of the chainis adapted to mate with a slot in a receiver on the door jamb. Byrotating the bolt disc inside the slot by means of the selector knob,the bolt disc becomes locked in the receiver. This is true for eitherchain lock" or safety chain" operation.

More specifically, the assembly has three modes of operation, i.e.,chain lock, safety chain and release. When the door is closed, theselector knob is manually thrust toward the receiver to cause the boltdisc to mate with a slot in the receiver and then manually flicked up ordown to lock the bolt disc and orient the chain to either chain lock orsafety chain the door. In the safety chain position, the chain isoriented with the common plane of the pivot pins parallel to the doorand the chain, due to the pivoting action of the links, is flexible tomovement of the door thereby permitting the door to be opened to theextent of the length of the chain. In the chain lock position, the chainis oriented with the common plane of the pivot pins perpendicular to thedoor and the chain is inflexible to movement of the door to positivelyprevent even a partial opening thereof. With the selector knob in therelease" position, the bolt disc, in alignment with the slot on thereceiver, is free to engage or disengage the receiver. When disengagedfrom the receiver or when the door is closed in the safety chain mode,the chain retracts into the barrel under the force of the spring.

Still other objects and advantages of the present invention will becomereadily apparent to those skilled in this art from the followingdetailed description, where I have shown and described only thepreferred embodiment of the invention, simply by way of illustration ofthe best mode contemplated by me of carrying out my invention. As willbe realized, the invention is capable of other and differentembodiments, and its several details are capable of modification invarious obvious respects, all without departing from the invention.Accordingly, the drawings and description are to be regarded asillustrative in nature. and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a top sectional view of theapparatus of the present invention with the door closed and the chainoriented in the chain lock mode;

FIG. 2 is a top sectional view of the apparatus with the chain orientedin the safety chain mode and the door opened to the extent of the lengthof the chain;

FIGS. 3a and 3b are views of the receiver taken along the line 33 inFIG. I showing the bolt disc in the chain lock and safety chain modes,respectively;

FIG. 4 is a front view of the barrel with a portion removed to show theinterior thereof; and

FIG. 5 is a sectional view taken along the line S5 in FIG. 1 showing theselector knob and the three posi tions thereof.

DETAILED DESCRIPTION OF THE DRAWING With reference to FIG. I, a chaindoor bolt assembly is mounted inside a door 12 adjacent a door jamb I4.The door 12 is closed against a door stop moulding l3 and latched to areceiver 15 with the assembly 10. The assembly 10 comprises a barrel l6enclosing a chain 18 and a chain guide, generally designated by thereference numeral 20. The chain guide 20 is fork-like, being formed oftwo fingers 22 and 24 (FIG. 2) secured to a drum 26. The chain I8 isheld captive between the fingers to lie along the axis 25 of the barrelI6.

A selector knob or lever 28 having a neck 29 and a gripping portion 30is secured to the drum 26 through a T-shaped slot 31 in the barrel 16.The drum 26 is freely moveable inside the barrel I6 limited by the action of the neck 29 of the selector knob 28 against the rim forming theT'shaped slot 3].

One end of the chain is connected to an anchor 32 which is disc-shapedwith openings to allow sliding along the fingers 22 and 24 of the chainguide 20. As the chain is withdrawn from the barrel, the anchor slidesalong the axis 25 (see FIG. I) of the barrel 16 until the limit ofmovement is reached, as shown in FIG. 2.

An end portion 38 of the barrel I6, mounted to the edge of the door 12adjacent the receiver I5, is secured to the barrel by the threadedcoupling 42. The receiver I5 is anchored to the jamb 14 with screws 36and, similarly, the end portion 38 may be anchored to the door withscrews (not shown). It is best to provide all screws with tamper-proofheads (see FIGS. 3a, 3b) to prevent unauthorized entry by removal of thelatch. As a further safety feature, the head of the center screw 36 onthe receiver 15 is totally blocked from access by the bolt disc 33 inthe safety chain position of FIG. 2.

A spring 37 inside the barrel l6 resiliently separates the anchor 32from the end portion 38. When the chain 18 is withdrawn from the barrel16 during opening of the door in the chain lock mode, the spring 37 iscompressed by the anchor 32. The limit of movement occurs when thespring 37 bottoms out (FIG. 2). A force tending to retract the chainback into the barrel is exerted on the door, thus automatically urgingthe door closed at all times in this mode. To hold the door open forventilation, any appropriate stop may be placed in the door in the wellknown manner.

To effect the attachment of the chain 18 to the reeeiver 15, thereceiver 15 contains an oblong slot 44 for receiving the bolt disc 33.The bolt 33 is oblong to match and mate with the slot 44 when the twoparts are aligned.

The slot 44 is formed of an outer portion having a first width W, (FIG.2) corresponding to the smaller dimension D of the bolt disc 33 (FIG.3a) and an inner portion having a second width W corresponding to thelarger dimension D of the bolt disc 33. When the bolt disc 33 is matedwith the slot 44 and rotated either clockwise or counterclockwise forsafety chain or chain lock operation, the bolt disc 33 becomes lockinglyengaged in the receiver, as shown in FIGS. 3a and 3b.

Referring to FIG. 5, the selector knob 28 is secured to the drum 26 bymeans of a bolt 52 which is screwed down into a tapped bore 54 in thedrum 26. The knob 28 is seated against a chamfered portion 56 of thedrum 26 and is held to the bolt 52 with a set screw 58 inserted throughthe neck 29 of the knob.

The chain 18 is formed of a plurality of links 46 seriallyinterconnected to each other with pivot pins 48 (see FIGS. 2 and 4).Each link 46 is formed ofa plurality of leaves jointed together injuxtaposition by the pivot pins 48 (see FIGS. 3a and 4). Preferably,each link consists of four inner leaves and five outer leaves, each leafhaving a thickness of 0.040 inch, but the particular number of leaves orthickness thereof is not crit ical. For example, another suitablestructure would be five inner and six outer leaves of 0.031 inchmaterial. The number of links 46 on the chain 18 corresponds to thedistance from the end portion 38 of the barrel 16 to the drum 26 whenthe chain is retracted. The disc 33 fits in the end portion and theanchor 32 abuts the drum 26 when the knob 28 is moved to any position onthe cross piece of T'shaped slot 31 (see FIG. I).

The pivot pins 48 lie in a common plane P and the chain is flexible onlyin a plane normal to the common plane by the pivoting action of thelinks. In FIG. I, the chain 18 is oriented with the common plane of thepivot pins 48 perpendicular to the vertical axis of the door 12 with thebolt disc 33 engaged with the receiver 15. It is apparent that thechain, oriented as shown, is not flexible to door movement and preventsin a positive manner the door 12 from opening even partially. On theother hand, as shown in FIG. 2, when the chain is oriented with thecommon plane P of the pivot pins parallel to the door, the chain isflexible to door move ment (in the plane of the paper, FIG. 2) and thedoor can be opened to the extent of the length of the chain when fullyretracted from the barrel 16.

The selector knob 28 can be placed in any of three positions, ie, chainlock, release and safety chain. In FIG. 5, the slot 31 is T-shaped. Thecross piece of the T includes an upper portion 60 for chain lock, alower portion 62 for safety chain and a middle portion 64 for release.The release portion 64 is displaced along the axis of the barrel fromthe positions 60 and 62. When the selector knob 28 is in the releaseposition 64, the chain 18 is fully retracted into the barrel under theforce of the spring 37 and the bolt disc 33 is seated in the end portion38.

In the release mode, the chain 18 is oriented obliquely (at 45) to thedoor and the bolt disc 33 is aligned with the slot 44 in the receiver 15as shown in FIG. 4.

When the selector knob 28 is manually displaced toward the left forchain lock or safety chain operation, the bolt disc 33 enters the slot44 in the receiver and just abuts the inside surface 66 thereof as theselector knob strikes the end 68 of the slot 31. When the selector knob28 is then flicked upwardly to the chain lock position, the drum 26,chain guard 20, chain 18 and bolt disc 33 rotate approximately 45 tolock the bolt disc in the inner portion W of the receiver slot 44, asbest shown in FIG. 3a. In the chain lock mode, the common plane P of thepins 48 of the chain 18 is substantially perpendicular to the door andthe chain, rigid to door movement, and thereby positively holds andprevents the door from opening even partially.

When the selector knob 28 is flicked downwardly to the safety chainposition, the chain 18 and bolt disc 33 are oriented as shown in FIG.3b. The bolt disc is now again locked within inner portion W of the slot44 of the receiver 15 but ninety degrees from the original lockedposition. The common plane P of the pins 48 is oriented parallel to thedoor as a consequence. Thus in safety chain operation, the chain 18 isflexible to door movement. As the door is opened, the first links drawnfrom the barrel 16 are pulled contiguously along slot 44 providingenough clearance between the door 12 and receiver for the thickness ofthe chain. As the door 12 is opened further, the chain 18 continues tobe drawn outwardly from the barrel 16 against the force of the spring37. Then when the door is subsequently closed, the action of the spring27 against the anchor 32 causes the chain 18 to automatically retractinto the barrel 16.

To release the bolt disc 33 from the receiver 15, the selector knob 28is manually placed in the release position 64, and the bolt disc 33, nowin alignment with the slot 44, disengages from the receiver to seat intothe end portion 38 under the force of the spring 37.

Thus, the assembly 10 has three modes of operation, i.e., a chain lockmode with the selector knob 28 positioned in the upper portion 60 of theT-shaped slot 31 to secure the door completely closed, a safety chainmode with the selector knob positioned in the lower portion 62permitting the door to be opened partially and a release mode with theknob positioned in the middle portion 64. The user can convenientlychoose between the three modes of operation with a flick of the selectorknob. Controlling all three modes ofoperation with one easy tomanipulate control is an important aspect of the present invention.

In this disclosure, there is shown and described only the preferredembodiment of the invention, but as aforementioned it is understood thatthe invention is capable of use in various other combinations andenvironments and is capable of changes or modifications within the scopeof the inventive concept as expressed herein. For example, to eliminatethe requirement of installing the assembly inside the door, the assemblycan be mounted to the outer surface of the door inside the dwelling withthe receiver mounted to the jamb adjacent the assembly. The chain 18 mayhave any desired number of leaves and may be any suitable gaugethickness to give the required strength to hold the door against anattempt of forced entry when the chain 18 is in the locked mode.

To finally review the operation, when the door is to be locked, the knob28 is moved in the T-slot 31 (to the left in FIG. 4) against the forceof the spring 37, and then upwardly to the chain lock position (FIG. 5).This action first moves the disc 33 into the receiver 15, and second,locks it in position (FIG. 3a). If it is desired to open the doorslightly (to view a caller, for example), the knob 30 is held forwardagainst edge 68 of T-slot 31 to resist the action of spring 37 (to keepthe disc 33 in the receiver 15) and then rapidly moved downwardlythrough ninety degrees directly to the safety chain position. Now thechain is orientated so as to allow flexing, and the door may be opened.To uncouple the latch and allow full opening of the door, the door isfirst closed and the knob is flicked upwardly. The knob stops upwardtravel after 45 at the release position, whereby upon the springautomatically retracts the chain and disconnects the disc 33. The doorcan now be opened.

In summary, there is provided a new and improved combination door latchand safety chain. Depending on the orientation of the connector pins 48between links 46 of the chain 18 with respect to the door, it is eitherheld fast in the closed position (FIG. 1) or allowed to open partially(FIG, 2). The latch positively holds the door closed by the single chain18, that also performs the chaining function. The T-shaped slot 31 andsingle control lever 28 gives easy, fool-proof operation. The chain 18is spring-loaded and hidden within the barrel 16 except when the door ispulled open slightly, such as when viewing a caller. Even when soextended, the chain 18 is controlled and the spring 37 tends to pull thedoor to the closed position.

What is claimed is: l. A combination door latch and safety chainassembly comprising:

chain means having a plurality of links serially interconnected withpivot means so as to be flexible in only one plane, said one plane beingperpendicular to a second plane passing through said pivot means;

support means for positioning said chain means with respect to a door;receiver means securable to a door jamb to engage said chain means, saidchain means being extendable between said door and said jamb; and

selector means for selectively orienting said chain means with respectto said door, whereby said chain means when engaged with said receivermeans is flexible in said one plane to allow movement of said door, saidmovement being when said chain is oriented with the second plane of saidpivot means thereof aligned substantially parallel to said door, andsaid chain means being inflexible in said one plane to prevent movementof said door when said chain is oriented with the second plane of saidpivot means substantially perpendicular to said door.

2. The assembly of claim 1 wherein said support means includes a barrelfor housing said chain means, said chain means being restricted to movealong the longitudinal axis of said barrel and extendable therefrom toengage said receiver means.

3. The assembly of claim 2 wherein said support means further includesspring means inside said barrel for biasing said chain means to retractinto said barrel along the axis thereof.

4. The assembly of claim 2 wherein said selector means includes chainguide means located inside said barrel and rotatable for orienting saidchain with respect to said door, and means external to said barrel forrotating said chain guide means.

5. The assembly of claim 4 wherein said chain guide means includes apair of fingers embracing said chain means and rotatable about thelongitudinal axis of said barrel; and said rotating means includes aselector knob extending through a slot in said barrel and connected tosaid chain guide.

6. The assembly of claim 5 including a drum freely mounted inside saidbarrel, said fingers secured to said drum and said selector knobfastened to said drum.

7. The assembly of claim 1 including a bolt disc secured to one end ofsaid chain means, and said receiver means containing a slot forreceiving said bolt disc.

8. A combination door latch and safety chain assembly comprising:

a chain having pivot means making the same flexible in only one plane,said chain positioned along the axis of a barrel, said barrel beingmountable to a door;

a receiver mountable to a door jamb to engage one end of said chain; and

a chain guide located inside said barrel for orienting the rotationalposition of said chain along said axis. said chain guide having:

a first rotational position for orienting said chain to be flexible toopening movement of said door;

a second rotational position for orienting said chain to be inflexibleto opening movement of said door; and

a third rotational position for selectively engaging and disengagingsaid one end of said chain from said receiver.

9. The assembly of claim 8 including spring means for automaticallyretracting said chain into said barrel.

10. The assembly of claim 9 including a selector knob accessibleexternally to said barrel and secured to said chain guide through a slotin said barrel.

1 l. The assembly of claim 8 including a bolt disc secured to said oneend of said chain, and wherein said receiver contains a slot forreceiving said bolt disc.

12. The assembly of claim ll wherein said bolt disc is oblong having afirst diameter and a second diameter, and said receiver slot includes afirst portion for receiv ing said bolt disc and a second portion forlocking said bolt disc to said receiver.

1. A combination door latch and safety chain assembly comprising: chainmeans having a plurality of links serially interconnected with pivotmeans so as to be flexible in only one plane, said one plane beingperpendicular to a second plane passing through said pivot means;support means for positioning said chain means with respect to a door;receiver means securable to a door jamb to engage said chain means, saidchain means being extendable between said door and said jamb; andselector means for selectively orienting said chain means with respectto said door, whereby said chain means when engaged with said receivermeans is flexible in said one plane to allow movement of said door, saidmovement being when said chain is oriented with the second plane of saidpivot means thereof aligned substantially parallel to said door, andsaid chain means being inflexible in said one plane to prevent movementof said door when said chain is oriented with the second plane of saidpivot means substantially perpendicular to said door.
 2. The assembly ofclaim 1 wherein said support means includes a barrel for housing saidchain means, said chain means being restricted to move along thelongitudinal axis of said barrel and extendable therefrom to engage saidreceiver means.
 3. The assembly of claim 2 wherein said support meansfurther includes spring means inside said barrel for biasing said chainmeans to retract into said barrel along the axis thereof.
 4. Theassembly of claim 2 wherein said selector means includes chain guidemeans located inside said barrel and rotatable for orienting said chainwith respect to said door, and means external to said barrel forrotating said chain guide means.
 5. The assembly of claim 4 wherein saidchain guide means includes a pair of fingers embracing said chain meansand rotatable about the longitudinal axis of said barrel; and saidrotating means includes a selector knob extending through a slot in saidbarrel and connected to said chain guide.
 6. The assembly of claim 5including a drum freely mounted inside said barrel, said fingers securedto said drum and said selector knob fastened to said drum.
 7. Theassembly of claim 1 including a bolt disc secured to one end of saidchain means, and said receiver means containing a slot for receivingsaid bolt disc.
 8. A combination door latch and safety chain assemblycomprising: a chain having pivot means making the same flexible in onlyone plane, said chain positioned along the axis of a barrel, said barrelbeing mountable to a door; a receiver mountable to a door jamb to engageone end of said chain; and a chain guide located inside said barrel fororienting the rotational position of said chain along said axis, saidchain guide having: a first rotational position for orienting said chainto be flexible to opening movement of said door; a second rotationalposition for orienting said chain to be inflexible to opening movementof said door; and a third rotational position for selectively engagingand disengaging said one end of said chain from said receiver.
 9. Theassembly of claim 8 including spring means for automatically retractingsaid chain into said barrel.
 10. The assembly of claim 9 including aselector knob accessible externally to said barrel and secured to saidchain guide through a slot in said barrel.
 11. The assembly of claim 8including a bolt disc secured to said one end of said chain, and whereinsaid receiver contains a slot for receiving said bolt disc.
 12. Theassembly of claim 11 wherein said bolt disC is oblong having a firstdiameter and a second diameter, and said receiver slot includes a firstportion for receiving said bolt disc and a second portion for lockingsaid bolt disc to said receiver.